Fire tube boiler

ABSTRACT

A fire tube boiler, comprising a jacket for containing water to be heated and a tube bundle designed to convey exhaust gases, which is accommodated within the jacket, the boiler comprising at least two furnaces with a corresponding burner connected to a single tube plate to which the tubes of the tube bundle are connected at one end, the tubes leading at their end into an exhaust gas collection chamber.

TECHNICAL FIELD

The invention relates to a fire tube boiler.

BACKGROUND ART

It is known that the heat source of thermal systems that require highpower is often provided by means of a battery of fire tube boilersconnected in parallel.

In conditions of high heat demand, such battery operates optimally,because all the boilers that compose it, conveniently balanced, areoperating, but when heat demand decreases, the burner of one or moreboilers is turned off: thus, the corresponding boiler remains unused,with all the negative consequences that notoriously arise from the lossof continuity of operation.

DISCLOSURE OF THE INVENTION

The aim of the present invention is to provide a fire tube boiler thatcan be installed as a heat source in thermal systems requiring highcapacities, ensuring continuity of operation as the heat demandconditions vary.

This aim and these and other objects which will become better apparenthereinafter are achieved by a fire tube boiler, according to theinvention, characterized in that it comprises the features disclosed inthe appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

Further characteristics and advantages of the invention will becomebetter apparent from the description of two preferred but not exclusiveembodiments of the fire tube boiler according to the invention,illustrated by way of non-limiting example in the accompanying drawings,wherein:

FIGS. 1 and 2 are views of a battery of boilers connected in parallelaccording to the background art, in two different operating conditions;

FIG. 3 is a sectional view of the boiler according to the inventionaccording to a first embodiment;

FIG. 4 is a view of the boiler according to the invention according to asecond embodiment.

WAYS OF CARRYING OUT THE INVENTION

With reference to FIGS. 1 and 2, the reference numerals 1 and 2designate two fire tube boilers according to the background art, whichare connected in parallel so as to form a battery.

The boilers 1 and 2 are identical, and therefore the boiler 1 comprisesa jacket 3 for containing the water 4 to be heated and is provided, atthe top, with a furnace 5 in which the flame produced by a burner 6develops.

The furnace 5 has a base shaped like a tube plate 7, from which aplurality of tubes 8 extend; said tubes are immersed in the water 4 tobe heated and convey the exhaust gases produced in the furnace 5 to achamber 9 for collection and conveyance to the stack.

The boiler 2, as mentioned, is identical to the boiler 1.

The situation shown in FIG. 1 is the full-capacity situation: the burner6 of the boiler 1 and the corresponding burner of the boiler 2 are on,as highlighted in the figure, and thus both boilers, balancedappropriately, are operating and the situation is optimum.

FIG. 2 instead shows the situation that occurs as a consequence of areduction in heat demand: the burner of the boiler 2 has shut down andaccordingly the entire boiler 2 remains unused.

FIG. 3 is a view of a first embodiment 10 of a boiler according to theinvention which comprises a jacket 11, for containing the water 12 to beheated, with connectors 11 a, 11 b respectively for inflow and outflow.

Inside the jacket 11 two furnaces 13 and 14 are provided, withcorresponding burners 13 a, 14 a, which have a common base constitutedby a tube plate 15, which is thus connected to both furnaces 13 and 14.

Tubes 16 of the tube bundle are connected to the tube plate 15, areimmersed in the water to be heated and convey the exhaust gasesgenerated in the two furnaces 13 and 14, or in at least one of them, toa chamber 17 for collection and conveyance to the stack.

When only one of the burners is operating, as is the case in FIG. 3, inwhich only a burner 13 a is on, the exhaust gases that it producesaffect all the tubes of the tube bundle, according to the arrows in thefigure, with consequent full use of the boiler and with the additionaladvantageous feature of achieving a great reduction in the temperatureof the exhaust gases in output, with consequent increase in efficiency,due to the large exchange surface that is offered to the exhaust gasesin the indicated condition.

FIG. 4 shows a second embodiment of the invention, in which two furnaces18 and 19, with respective burners 18 a, 19 a, instead of being side byside as in the embodiment of FIG. 3, are superimposed, but in any casealways both connected to a tube plate 20 to which tubes 21 of the tubebundle are connected; such tubes are immersed in the water to be heatedand convey the exhaust gases produced in both furnaces, or in only oneof them, as is the case of FIG. 4, in which only the burner 18 a is on,with the flow of exhaust gases highlighted by the arrows, to acollection chamber 22.

In practice it has been found that the boiler according to the inventionfully achieves the intended aim.

The described invention is susceptible of numerous other modificationsand variations, all of which are within the scope of the appendedclaims: moreover, all the details may be replaced with other technicallyequivalent elements.

The disclosures in Italian Patent Application No. MI2010A001418 fromwhich this application claims priority are incorporated herein byreference.

Where technical features mentioned in any claim are followed byreference signs, those reference signs have been included for the solepurpose of increasing the intelligibility of the claims and accordinglysuch reference signs do not have any limiting effect on theinterpretation of each element identified by way of example by suchreference signs.

1-3. (canceled)
 4. A fire tube boiler, comprising a jacket forcontaining water to be heated and a tube bundle designed to conveyexhaust gases, which is accommodated within said jacket, furthercomprising at least two furnaces with a corresponding burner connectedto a single tube plate to which tubes of said tube bundle are connectedat one end, said tubes leading at their end into an exhaust gascollection chamber.
 5. The boiler according to claim 4, wherein said atleast two furnaces are arranged side by side.
 6. The boiler according toclaim 4, wherein said at least two furnaces are arranged so that onelies above the other.